1. FIELD OF THE INVENTION
This invention relates to a novel laminate. More particularly, this invention relates to a laminate improved in interlaminar adhesion.
2. DESCRIPTION OF THE PRIOR ART
Hitherto, a number of attempts have been made to prepare various laminates either by bonding different materials to each other with the aim of giving the laminates the advantages of both materials or by putting one material between layers of another material with the aim of compensating the fault of the outer layer material. As materials for such laminates, there are used metallic foils such as aluminum foil or copper foil, paper and cellophane, as well as various thermoplastic resins such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, nylon, polycarbonate, polystyrene, high impact polystyrene, polyvinylidene chloride, ABS resin, and the like. These laminates are used in the form of a sheet, film, blow-minded article or the like.
These laminates are generally prepared by bonding sheets or films of the same material or different materials with a binder or by co-extruding the same material or different materials without using any binder.
Sometimes, however, a sufficient adhesion effect cannot be obtained with some kinds of materials to be laminated or some combinations of materials to be laminated. Particularly when a laminate is prepared by co-extrusion without using any binder, materials lacking mutual adhesion cannot be used. Therefore, when it is intended to prepare a laminate from materials lacking mutual adhesion by co-extrusion, a material having adhesiveness to both the materials is used as an adhesive layer. As such an adhesive material, there are used, for example, ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene block copolymer and the like. However, these materials still have problems in that adhesion effects are not necessarily sufficient when some kinds of materials are co-extruded and the resulting laminates are inferior in durability of adhesion, water-resistance, and the like.